Advice for simple set up for solar pump

[mixed 57]

On 1/12/2021 at 5:57 PM, Crossy said:

You have a 330W panel.

 

If you have a real MPPT controller driving a 12V battery 330W = 28A so you need a >30A charge controller. But you must check the max input voltage, most of these small controllers are less than the output of a 330W panel!!

I'm trying to figure this out, the controller says it's rated for up to 390w at 12v. So it should be OK? Below is info from my panel, if somebody could use this to tell me the parameters I'll need to check when looking for a controller.

 

This is from the back of the panel.

 

These are the specs for the controller:

Rated charging current: 30a | 40a | 50a| 60a | 100a

Rated discharge current: 10a | 20a | 20a | 30a | 30a

Solar photovoltaic voltage :12V battery with 18V solar panel, 24V battery with 36 solar panel

Full Voltage Value : Lithium Battery (12.2V) | B02 Colloidal Battery (14.2V) | B03 Open Cell (14.6V)

Floating Charge Voltage : 13.7 V ( Default, Adjustable )

Discharge cutoff voltage::10.7 V ( default, adjustable )

Discharge recovery voltage: 12.6 V ( default, adjustable )

Standby current :10mAUSB 

Output : 5V / 2A MAX

Operating temperature:- 35 - 60

[Crossy 27,042]

31 minutes ago, mixed said:

I'm trying to figure this out, the controller says it's rated for up to 390w at 12v. So it should be OK? Below is info from my panel, if somebody could use this to tell me the parameters I'll need to check when looking for a controller.

 

This is the problem, maximum of only an 18V panel with a 12V battery.

 

31 minutes ago, mixed said:

Solar photovoltaic voltage :12V battery with 18V solar panel, 

 

Your panel is 37.5V at max power.

 

For the controller to achive the 300W you would be looking at 2 x 150W 18V panels.

 

[mixed 57]

Thanks Crossy. From the info I've supplied can you tell me the parameters for a charge controller that will work with my 330w panel?

 

The controller that you linked to is more expensive than the panel itself. Do I need an expensive controller because I bought a larger panel and will I need several controllers if I have several panels? That controller is only suitable for 720w, which is 2 panels.

 

Originally I was thinking controllers were a small part of the cost, now it seems otherwise. Do I really need a PMMT controller in Thailand?

[maxpower 1,833]

1 hour ago, mixed said:

The controller that you linked to is more expensive than the panel itself. Do I need an expensive controller because I bought a larger panel and will I need several controllers if I have several panels? That controller is only suitable for 720w, which is 2 panels.

 

Originally I was thinking controllers were a small part of the cost, now it seems otherwise. Do I really need a PMMT controller in Thailand?

 

Unfortunately you have not chosen the best panel voltage for PWM charging a 12V battery. This probably came about through thinking only about the watts of panel and pump.

 

If you do manage to successfully get a PWM controller to charge your 12V battery with 330W 46V panel you will be throwing away power. This is often where the confusion starts when PWM charge controllers fail to deliver.

 

Before moving forward its best that you understand a little about power point and why MPPT control will help compensate for your mistake.

 

This video from ace tinkerer Julian Ilett breaks the ice.

 

 

[mixed 57]

34 minutes ago, maxpower said:

Unfortunately you have not chosen the best panel voltage for PWM charging a 12V battery. This probably came about through thinking only about the watts of panel and pump.

 

If you do manage to successfully get a PWM controller to charge your 12V battery with 330W 46V panel you will be throwing away power. This is often where the confusion starts when PWM charge controllers fail to deliver.

 

Before moving forward its best that you understand a little about power point and why MPPT control will help compensate for your mistake.

 

I am happy to get an MPPT controller, but want to know it's limitations so I don't end up in a similar situation. My concern with the controller Crossy posted was it's maximum rating of 740w, which is only 2 panels. I

 

I realize there is a lot to learn, originally I thought the panels were a 'much of a muchness' and with a cheap controller and 300w panel I'd be OK. As with all things the devil's in the detail. Is the panel I've bought a really bad choice?

[Crossy 27,042]

35 minutes ago, mixed said:

I am happy to get an MPPT controller, but want to know it's limitations so I don't end up in a similar situation. My concern with the controller Crossy posted was it's maximum rating of 740w, which is only 2 panels. I

 

I realize there is a lot to learn, originally I thought the panels were a 'much of a muchness' and with a cheap controller and 300w panel I'd be OK. As with all things the devil's in the detail. Is the panel I've bought a really bad choice?

 

You can parallel multiple controllers on the same batteries if you want, just make sure the panel ends are separate.

 

If you want to go over a few 00 watts you would be better going for a higher battery voltage of 24V or 48V. The same current at the higher voltages means more power via the same controller.

 

For now I would get a more suitable MPPT controller like I linked to so your current system will work correctly. You can decide how to expand when and if the time comes.

[mixed 57]

5 minutes ago, Crossy said:

For now I would get a more suitable MPPT controller like I linked to so your current system will work correctly. You can decide how to expand when and if the time comes.

Thanks Crossy.